Comprehensive Assessment of humpback whales in Oceania

Humpback whales
were once abundant around islands of the South Pacific
during the winter breeding season. These populations nearly
disappeared as a result of intensive hunting following World
War II, particularly the large-scale illegal whaling by the
Soviet Union in the 1960s.

More than 50 years after
the end of commercial whaling, how many humpback whales are
there in the South Pacific and to what extent have these
populations recovered to pre-whaling numbers?

To
answer these questions, members of the South Pacific Whale
Research Consortium, supported by the Secretariat of the
Pacific Regional Environment Programme (SPREP), have been
working with the Scientific Committee of the International
Whaling Commission to complete the first Comprehensive
Assessment of humpback whales in the Southern
Hemisphere.

The South Pacific Whale Research
Consortium was formed 15 years ago to coordinate research by
independent scientists both within and outside the region,
and to provide management advice on the conservation of
whales and dolphins in the waters of Oceania.

One of
the Consortium’s primary goals has been to assess the
recovery of humpback whales that once migrated from
Antarctic feeding grounds to winter breeding grounds around
Pacific island nations. Using photo-identification records
and genetic samples from more than 2,000 individual whales,
Consortium members provided the first estimates of
abundance, descriptions of genetic differentiation and
documentation of migratory movement for humpback whales
throughout Oceania. SPREP was an early partner in this
endeavour, and has continued to support the Consortium
throughout the assessment process.

Now, the results
of this long-term, collaborative research have been
integrated into the first Comprehensive Assessment of
humpback whales in Oceania, completed at this year’s
meeting of the International Whaling Commission in Bled,
Slovenia, in May. Using data contributed by the Consortium
on the abundance, distribution, genetic differentiation and
migratory movements of humpback whales from eastern
Australia, New Caledonia, New Zealand, Tonga, American Samoa
and Samoa, the Cook Islands and French Polynesia. The
Scientific Committee developed a mathematical model to
reconstruct the history of decline and slow recovery from
20th century whaling.

The Scientific Committee
concluded that humpback whales in Oceania once numbered more
than 14,000, but by 1966, they were reduced to less than 1%
of this number. Since that time, whales in this vast region
have increased slowly to about 5,000, or about 37% of their
pre-exploitation numbers. Given the current rate of
increase, it may be another three decades before this
population is fully recovered.

“The Comprehensive
Assessment confirmed how close the humpback whale population
of Oceania came to extinction,” says Scott Baker, a
Consortium member and Scientific Delegate to the
International Whaling Commission. “There may have been
fewer than 40 mature females surviving in this vast region
after the catastrophic programme of illegal Soviet whaling
in the early 1960s.”

The importance of
understanding regional trends in humpback whales was also
highlighted in a recent publication, led by Consortium
members, on genetic isolation among oceanic populations.
This isolation was found to be so profound that the authors
propose to recognise three subspecies of humpback whale,
including Megaptera novaeangliae australis from the Southern
Hemisphere.

To help ensure that this recovery
continues, Consortium members have worked with SPREP and the
governments of New Caledonia, Niue, the Cook Islands, French
Polynesia, Tonga and Samoa to implement conservation
management policies.

“These island nations have
declared large sanctuaries to promote the recovery of these
depleted populations and provide the opportunity for local
economic benefit through whale watching” says Mike
Donoghue, Threatened and Migratory Species Adviser for
SPREP.

The Consortium is planning to collaborate
with SPREP to conduct further surveys and analysis to
estimate the current status of Oceania humpbacks during
2016.

Funding for the Consortium’s research on
humpback whales in Oceania has been provided by the
International Fund for Animal Welfare (IFAW), the Australian
Marine Mammal Centre through the Southern Ocean Research
Partnership (SORP), Fonds Pacifique and the Secretariat of
the Pacific Regional Environment Programme (SPREP).

Nelson Mandela, then Deputy President of the African National Congress of South Africa, raises his fist in the air while addressing the Special Committee Against Apartheid in the General Assembly Hall. UN Photo/P. Sudhakaran More>>